By utilizing a communication device onboard a mobile object such as a vehicle, direct communication between the mobile object and various target objects is realized. Communication between a communication device onboard a mobile object and various other communication devices is called vehicle-to-X (V2X) communication. For V2X communication, communication systems utilizing dedicated short range communications (DSRC) have been investigated thus far, but recently, investigation into communication systems utilizing mobile phone communication standards such as Long Term Evolution (LTE) is progressing. Note that a system related to the LTE communication standard is disclosed in Patent Literature 1 below, for example.